The entire left hand side of my left breast has gone hard and hurts like hell. Why is this and what should I do about it? I think it has been gradually happening over the course of the day, but it has been DD's christening day and very busy and stressful with about 25 people to feed and entertain in my house that is not big enough for 25 people, so I didn't pay attention until it hurt too much to ignore. It hurts all the time not just when feeding. I really noticed it hurting this afternoon and have mostly fed her on that side since in case it is something that can be cleared by feeding. DD is 6 months old if that is relevant. Please tell me it doesn't need me to see a dr as it will probably take days and days to get an appointment.